1. Field
The invention relates to radiation detectors particularly the types which can separate very narrow band line spectra so as to identify types and wavelengths of laser sources.
2. Prior Art
Numerous devices have been devised to study the line spectra of radiant sources such as the sun and more recently lasers. The usual arrangement includes a diffraction grating or prism in the radiation path and some type of detector which scans the resulting separated spectral lines. Effective gratings are very expensive and the detection system must be very precise to detect the small separations achieved. A number of lasers are now being developed for use on the battlefield both as surveillance devices and offensive weapons per se. These weapons are mainly intended to blind foot soldiers and vehicle operators. They also present a special threat to equipment having optical systems that intensify light with convergent focussing and systems having sensitive detectors like the Army's Forward Looking Infrared Viewer (FLIR). Since these weapons operate only in very narrow frequency bands, it is possible that their radiation may be rejected by suitable filters without the need to blindfold equipment operators or shut down needed equipment. The array of lasers has become too vast to permit proper protection from all of them, but in most real world situations only one or at most a few different lasers need be dealt with. The solution to this problem requires a knowledge of which frequencies are involved at a specific locale. This, in turn, requires an inexpensive, rugged, portable and highly accurate spectrometer. An object of the present invention is to provide such a spectrometer.